Giani20151AGianiLogos VerlagBerlin, Germany2014-00-00Throughout the day, our senses provide us with a rich stream of information about the environment: We see colours and shapes, hear music or smell food. With seemingly no effort, the human brain integrates these signals to create a conscious sensory experience of the external world. Yet, this sensory experience is not a truthful representation of the physical world. Instead, it is crucially shaped by a variety of processes, two of which are the focus of the current work: multisensory integration and awareness.
Yet, in contrast to their impact, relatively little is known about the mechanisms that enable perceptual awareness within a multisensory world. For example, does multisensory integration occur automatically or are higher order cognitive processes (such as awareness) necessary to bind the information? And where does awareness emerge within the human brain? The current work describes three experimental studies, which were designed to provide further insights into auditory and visual perception and the human brain.Tübingen, Univ., Diss., 2014nonotspecifiedhttp://www.kyb.tuebingen.mpg.de/published120From multiple senses to perceptual awareness15017188261501715422SchrecklmannGTLRPVHHF20163MSchecklmannAGianiSTupakBLangguthVRaabTPolakCVárallyayWHarnischMJHerrmannAJFallgatter2016-03-00234165175Restorative Neurology and NeurosciencePurpose:
Clinical effects of repetitive transcranial magnetic stimulation (rTMS) in chronic tinnitus are moderate. More precise coil localisation strategies, innovative stimulation protocols, and identification of predictors for treatment response were proposed as promising attempts to enhance treatment efficacy. In this pilot study we investigated neuronavigated continuous theta burst TMS (cTBS).
Methods:
Twenty-three patients received neuronavigated cTBS over the left primary auditory cortex in a randomized sham-controlled trial (verum = 12; sham = 11). Treatment response was evaluated with tinnitus questionnaires and numeric rating scales. Immediate change in numeric rating scales during the first session was used as predictor for treatment response.
Results:
Tinnitus was significantly reduced after treatment, but there were no superior effects between verum vs. sham treatment. Immediate change in the first treatment session predicted the response to treatment only in the verum group.
Conclusions:
In our study, verum cTBS was not superior to sham which highlights the persistent need for improving non-invasive brain stimulation techniques for the treatment of tinnitus. Future research should focus on the transfer of positive single session effects to daily treatment trials.nonotspecifiedhttp://www.kyb.tuebingen.mpg.de/published10Neuronavigated left temporal continuous theta burst stimulation in chronic tinnitus1501718826GianiBOKN20153ASGianiPBelardinelliEOrtizMKleinerUNoppeney2015-11-00122203–213NeuroImageIn everyday life, our auditory system is bombarded with many signals in complex auditory scenes. Limited processing capacities allow only a fraction of these signals to enter perceptual awareness. This magnetoencephalography (MEG) study used informational masking to identify the neural mechanisms that enable auditory awareness. On each trial, participants indicated whether they detected a pair of sequentially presented tones (i.e., the target) that were embedded within a multi-tone background.
We analysed MEG activity for ‘hits’ and ‘misses’, separately for the first and second tones within a target pair. Comparing physically identical stimuli that were detected or missed provided insights into the neural processes underlying auditory awareness. While the first tone within a target elicited a stronger early P50m on hit trials, only the second tone evoked a negativity at 150 ms, which may index segregation of the tone pair from the multi-tone background. Notably, a later sustained deflection peaking around 300 and 500 ms (P300m) was the only component that was significantly amplified for both tones, when they were detected pointing towards its key role in perceptual awareness.
Additional Dynamic Causal Modelling analyses indicated that the negativity at 150 ms underlying auditory stream segregation is mediated predominantly via changes in intrinsic connectivity within auditory cortices. By contrast, the later P300m response as a signature of perceptual awareness relies on interactions between parietal and auditory cortices.
In conclusion, our results suggest that successful detection and hence auditory awareness of a two-tone pair within complex auditory scenes rely on recurrent processing between auditory and higher-order parietal cortices.nonotspecifiedhttp://www.kyb.tuebingen.mpg.de/published-203Detecting tones in complex auditory scenes15017154221501718826AllerGCWN20153MAllerAGianiVConradMWatanabeUNoppeney2015-02-0016918Frontiers in Integrative NeuroscienceTo interact effectively with the environment the brain integrates signals from multiple senses. It is currently unclear to what extent spatial information can be integrated across different senses in the absence of awareness. Combining dynamic continuous flash suppression and spatial audiovisual stimulation, the current study investigated whether a sound facilitates a concurrent visual flash to elude flash suppression and enter perceptual awareness depending on audiovisual spatial congruency. Our results demonstrate that a concurrent sound boosts unaware visual signals into perceptual awareness. Critically, this process depended on the spatial congruency of the auditory and visual signals pointing towards low level mechanisms of audiovisual integration. Moreover, the concurrent sound biased the reported location of the flash as a function of flash visibility. The spatial bias of sounds on reported flash location was strongest for flashes that were judged invisible. Our results suggest that multisensory integration is a critical mechanism that enables signals to enter conscious perception.nonotspecifiedhttp://www.kyb.tuebingen.mpg.de/published7A spatially collocated sound thrusts a flash into awareness1501718826150171542115017188241501715422SchecklmannGTLRPVHHF20143MSchecklmannAGianiSTupakBLangguthVRaabTPolakCVárallyayWHarnischMJHerrmannAJFallgatter2014-11-00894203201418Neural PlasticityObjective. Several neuroscience tools showed the involvement of auditory cortex in chronic tinnitus. In this proof-of-principle study we probed the capability of functional near-infrared spectroscopy (fNIRS) for the measurement of brain oxygenation in auditory cortex in dependence from chronic tinnitus and from intervention with transcranial magnetic stimulation. Methods. Twenty-three patients received continuous theta burst stimulation over the left primary auditory cortex in a randomized sham-controlled neuronavigated trial (verum = 12; placebo = 11). Before and after treatment, sound-evoked brain oxygenation in temporal areas was measured with fNIRS. Brain oxygenation was measured once in healthy controls . Results. Sound-evoked activity in right temporal areas was increased in the patients in contrast to healthy controls. Left-sided temporal activity under the stimulated area changed over the course of the trial; high baseline oxygenation was reduced and vice versa. Conclusions. By demonstrating that rTMS interacts with auditory evoked brain activity, our results confirm earlier electrophysiological findings and indicate the sensitivity of fNIRS for detecting rTMS induced changes in brain activity. Moreover, our findings of trait- and state-related oxygenation changes indicate the potential of fNIRS for the investigation of tinnitus pathophysiology and treatment response.nonotspecifiedhttp://www.kyb.tuebingen.mpg.de/published7Functional Near-Infrared Spectroscopy to Probe State- and Trait-Like Conditions in Chronic Tinnitus: A Proof-of-Principle Study15017188261501715422GianiOBKPN20123ASGianiEBOrtizPBelardinelliMKleinerHPreisslUNoppeney2012-04-002601478–1489NeuroImageTo form a unified percept of our environment, the human brain integrates information within and across the senses. This MEG study investigated interactions within and between sensory modalities using a frequency analysis of steady-state responses that are elicited time-locked to periodically modulated stimuli. Critically, in the frequency domain, interactions between sensory signals are indexed by crossmodulation terms (i.e. the sums and differences of the fundamental frequencies). The 3x2 factorial design, manipulated (1) modality: auditory, visual or audiovisual (2) steady-state modulation: the auditory and visual signals were modulated only in one sensory feature (e.g. visual gratings modulated in luminance at 6 Hz) or in two features (e.g. tones modulated in frequency at 40 Hz & amplitude at 0.2 Hz). This design enabled us to investigate crossmodulation frequencies that are elicited when two stimulus features are modulated concurrently (i) in one sensory modality or (ii) in auditory and visual modalities. In support of within-modality integration, we reliably identified crossmodulation frequencies when two stimulus features in one sensory modality were modulated at different frequencies. In contrast, no crossmodulation frequencies were identified when information needed to be combined from auditory and visual modalities. The absence of audiovisual crossmodulation frequencies suggests that the previously reported audiovisual interactions in primary sensory areas may mediate low level spatiotemporal coincidence detection that is prominent for stimulus transients but less relevant for sustained SSR responses. In conclusion, our results indicate that information in SSRs is integrated over multiple time scales within but not across sensory modalities at the primary cortical level.nonotspecifiedhttp://www.kyb.tuebingen.mpg.de/published-1478Steady-state responses in MEG demonstrate information integration within but not across the auditory and visual senses15017188261501715422DreslerGRSSF20103TDreslerASGianiCReinsbergerPScheuerpflugGStöberAJFallgatter2010-10-001011712091212Journal of Neural TransmissionWe investigated a patient with severe catatonic schizophrenia (manneristic catatonia according to Karl Leonhard) treated with electroconvulsive therapy (ECT) after pharmacological approaches did not result in any clinical improvement. Before and after nine ECT sessions a double-pulse transcranial magnetic stimulation (TMS) paradigm was used to measure intracortical inhibition (ICI) which has been shown to be reduced in a significant proportion of patients with schizophrenia. Although the patient showed no remission regarding some psychomotor aspects after ECT, we found an increase in ICI and a remarkable clinical improvement of catatonic omissions which might be due to changes in the GABAergic system.nonotspecifiedhttp://www.kyb.tuebingen.mpg.de/published3Electroconvulsive therapy resolves cortical inhibition and manneristic omissions in a chronic catatonic patientGianiN20127ASGianiUNoppeneyParis, France2012-08-008th International Conference on Biomagnetism (BIOMAG 2012)nonotspecifiedhttp://www.kyb.tuebingen.mpg.de/published0Awareness related auditory scene analysis: A processing cascade enables a tone pair to be segregated from background and enter awareness15017154221501718826GianiEBKPN20117AGianiOErickPBelardinelliMKleinerHPreisslUNoppeneyHeiligkreuztal, Germany2011-10-002712th Conference of Junior Neuroscientists of Tübingen (NeNA 2011)To form a unified percept of our environment, the human brain integrates information within
and across the senses. This MEG study investigated interactions within and between sensory
modalities using a frequency analysis of steady-Ââstate responses (SSR) to periodic auditory
and/or visual inputs. The 3x3 factorial design, manipulated (1) modality (auditory only, visual
only and audiovisual) and (2) temporal dynamics (static, dynamic1 and dynamic2). In
the static conditions, subjects were presented with (1) visual gratings, luminance modulated
at 6Hz and/or (2) pure tones, frequency modulated at 40 Hz. To manipulate perceptual synchrony,
we imposed additional slow modulations on the auditory and visual stimuli either at
same (0.2 Hz = synchronous) or different frequencies (0.2 Hz vs. 0.7 Hz = asynchronous).
This also enabled us to investigate the integration of two dynamic features within one sensory
modality (e.g. a pure tone frequency modulated at 40Hz & amplitude modulated at 0.2Hz)
in the dynamic conditions. We reliably identified crossmodulation frequencies when these
two stimulus features were modulated at different frequencies. In contrast, no crossmodulation
frequencies were identified when information needed to be combined from auditory
and visual modalities. The absence of audiovisual crossmodulation frequencies suggests that
the previously reported audiovisual interactions in primary sensory areas may mediate low
level spatiotemporal coincidence detection that is prominent for stimulus transients but less
relevant for sustained SSR responses. In conclusion, our results indicate that information in
SSRs is integrated over multiple time scales within but not across sensory modalities at the
primary cortical level.nonotspecifiedhttp://www.kyb.tuebingen.mpg.de/published-27Steady-state responses in MEG demonstrate information integration within but not across the auditory and visual senses15017154221501718826GianiOBKPN20117ASGianiEBOrtizPBelardinelliMKleinerHPreisslUNoppeneyQuébec City, Canada2011-06-0017th Annual Meeting of the Organization for Human Brain Mapping (HBM 2011)How does the brain integrate information within and across sensory modalities to form a unified percept? This question has previously been addressed using transient stimuli, analyzed in the time domain. Alternatively, sensory interactions can be investigated using frequency analyses of steady state responses (SSRs). SSRs are elicited by periodic sensory stimulation (such as frequency modulated tones). In the frequency domain, 'true' signal integration is reflected by non-linear crossmodulation terms (i.e. the sums and differences of the individual SSR frequencies). In addition, two signals may modulate the amplitude of the fundamental and harmonic frequencies of one another. Using visual (V) and auditory (A) SSRs, we investigated whether A and V signals are truly integrated as indexed by crossmodulation terms or simply modulate the expression of each other's dominant frequencies. To manipulate perceptual synchrony, we imposed additional slow modulations on the auditory and visual SSRs either at same or different frequencies. This also enabled us to investigate the integration of two dynamic features within one sensory modality.nonotspecifiedhttp://www.kyb.tuebingen.mpg.de/fileadmin/user_upload/files/publications/2011/HBM-2011-Giani.pdfpublished0Using steady state responses in MEG to study information integration within and across the senses15017154221501718826GianiHVPHSSF20097ASGianiWHamischCGVarallyayTPolakRHagenLSolymosiATSackAJFallgatterDoorwerth, Netherlands2009-06-008th Dutch Endo-Neuro-Psycho Meeting (ENP 2009)People suffering from chronic tinnitus continuously experience auditory noise in the absence of any auditory stimulation. This agonising phantom perception has been related to an enhanced activation of the auditory cortex. Low-frequency transcranial magnetic stimulation (TMS) is a convenient tool that can effectively inhibit this hyperactivity and attenuate the severity of tinnitus. Yet, it has been shown that theta burst stimulation (TBS) inhibits cortical activation more effectively than conventional low-frequency TMS. Hence, TBS might likewise be more effective in relieving tinnitus patients’ distressing auditory perceptions. We aimed to evaluate the effect of two weeks of TBS treatment on tinnitus severity and cortical activation using a placebo controlled design. During each session, two trains of 200 theta bursts (one burst = 3 pulses, 50Hz) each were applied, resulting in a total of 1200 pulses. By means of a neuronavigation device, the TMS coil could be located exactly above the auditory cortex. Tinnitus severity was assessed using the tinnitus questionnaire, the tinnitus handicap inventory (THI) and a visual analogue scale. To evaluate the cortical activation, we depicted the hemodynamic response using near infrared spectroscopy (NIRS) at baseline and immediately after the last session. Lastly, the cortical excitability of the motor cortex was assessed using a double pulse TMS paradigm. In order to be able to depict immediate and long term effects of TBS on the cortical excitability, the paradigm was carried out six times: before and after session one, six and ten. Preliminary results reveal that TBS can effectively improve tinnitus severity. In some patients, the score on the tinnitus questionnaire and on the tinnitus handicap inventory declined by maximally 50%. The effect of TBS on hemodynamic response (NIRS) and on cortical excitability (double pulse TMS) will be discussed and related to changes in tinnitus severity.nonotspecifiedhttp://www.kyb.tuebingen.mpg.de/published0Treating Tinnitus with TMS: theta burst stimulation and the relief of auditory phantom perceptionsGiani201415AGiani2014-05-00nonotspecifiedpublishedFrom multiple senses to perceptual awareness1501715422GianiSF200814ASGianiASackAJFallgatter2008-08-00nonotspecifiedpublishedTreating Tinnitus with TMS: Theta burst stimulation and the relive of auditory phantom perceptionsmasterGianiN2012_210AGianiUNoppeneyGianiHHVSPPSF200910ASGianiWHamischRHagenCGVarallayLSolymosiTPolakMPlichtaATSackAJFallgatter